【Android】使用Messenger实现进程间通讯

1 Messenger 简介

​ Messenger 类实现了 Parcelable 接口，用于进程间传输并处理消息，调用流程如下：

• Client 通过 bindService() 请求绑定 Service
• Service 通过 messenger_s.getBinder() 获取 IBunder 并返回 Client
• Client 通过 messenger_s =new Messenger(service) 获取 Service 的 Messenger
• Client 通过 msg_c2s.replyTo=messenger_c 将自己的 Messenger 绑定到 msg_c2s
• Client 通过 messenger_s.send(msg_c2s) 给 Service 发送消息
• Service 通过 messenger_c=msg_c2s.replyTo 获取 Client 的 Messenger
• Service 通过 messenger_c.send(msg_s2c) 给 Client 发送消息

​ 本文全部代码见→使用Messenger实现进程间通讯

2 项目结构

3 服务端 msger_S 代码

​ （1）创建服务

​ MyService.java

package com.example.msger_s;

import android.app.Service;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.util.Log;

public class MyService extends Service {
    Messenger messenger_c; //客户端的Messenger

    @Override
    public IBinder onBind(Intent intent) {
        return messenger_s.getBinder();
    }

    private Messenger messenger_s = new Messenger(new Handler() {
        @Override
        public void handleMessage(Message msg_c2s) {
            super.handleMessage(msg_c2s);
            receive(msg_c2s);
            messenger_c = msg_c2s.replyTo; //获取客户端的Messenger
            send();
        }
    });

    private void receive(Message msg) { //接收来自客户端的消息
        Bundle bundle = (Bundle) msg.obj;
        String msg_c2s = bundle.getString("msg_c2s");
        Log.e("MyService", "来自客户端的消息：" + msg_c2s);
    }

    private void send() { //给客户端返回消息
        Message msg = new Message();
        Bundle bundle1 = new Bundle();
        bundle1.putString("msg_s2c", "hello client");
        msg.obj = bundle1;
        try {
            messenger_c.send(msg);
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }
}

​ （2）注册服务

​ 在 AndroidManifest.xml 文件中 application 节点下注册 service，如下。

<service
     android:name=".MyService"
     android:exported="true">
     <intent-filter>
           <action android:name="com.xxx.msger_s"/>
           <category android:name="android.intent.category.DEFAULT" />
     </intent-filter>
</service>

​ （3）主 Activity

​ MainActivity.java

package com.example.msger_s;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

4 客户端 msger_C 代码

​ （1）设计布局

​ activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.example.msger_c.MainActivity">

    <EditText
        android:id="@+id/et_send"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:text="hello service"
        android:textSize="30dp"
        android:background="#ffcc66"/>

    <Button
        android:id="@+id/btn_send"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="30dp"
        android:textSize="30sp"
        android:text="发送"/>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="返回的消息："
        android:textSize="30sp"
        android:layout_marginTop="100dp"/>

    <TextView
        android:id="@+id/tv_receive"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:textSize="30sp"
        android:background="#ffcc66"
        android:layout_marginTop="20dp"/>
</LinearLayout>

​ 界面如下：

​ （2）主 Activity

​ MainActivity.java

package com.example.msger_c;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private Messenger messenger_s; //服务端的Messenger
    private EditText et_send;
    private Button btn_send;
    private TextView tv_receive;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {
        et_send = (EditText) findViewById(R.id.et_send);
        btn_send = (Button) findViewById(R.id.btn_send);
        tv_receive = (TextView) findViewById(R.id.tv_receive);
        btn_send.setOnClickListener(cl);
    }

    View.OnClickListener cl = new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            hideInputMethod(MainActivity.this, v); //关闭输入法
            if (v.getId()==R.id.btn_send) {
                String msg_c2s = et_send.getText().toString();
                sendMsg(msg_c2s);
            }
        }
    };

    private void sendMsg(String msg_c2s){
        if (messenger_s==null) {
            attemptToBindService();
        }
        Message msg = new Message();
        Bundle bundle = new Bundle();
        bundle.putString("msg_c2s",msg_c2s);
        msg.obj = bundle;
        msg.replyTo = messenger_c; //将客户端的Messenger传给服务端
        try {
            messenger_s.send(msg);
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }

    private Messenger messenger_c = new Messenger(new Handler() { //客户端的Messenger
        @Override
        public void handleMessage(Message msg) { //处理服务端返回的消息
            super.handleMessage(msg);
            Bundle bundle = (Bundle) msg.obj;
            String msg_s2c = bundle.getString("msg_s2c");
            tv_receive.setText(msg_s2c);
        }
    });

    private void attemptToBindService() {
        Intent intent = new Intent();
        intent.setAction("com.xxx.msger_s");
        intent.setPackage("com.example.msger_s");
        bindService(intent, conn, Context.BIND_AUTO_CREATE);
    }

    ServiceConnection conn = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            messenger_s = new Messenger(service); //获取服务端的Messenger
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            messenger_s = null;
        }
    };

    private void hideInputMethod(Activity act, View v) { //关闭输入法
        InputMethodManager imm = (InputMethodManager) act.getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.hideSoftInputFromWindow(v.getWindowToken(),0);
    }

    @Override
    protected void onStart() {
        super.onStart();
        if (messenger_s==null) {
            attemptToBindService();
        }
    }

    @Override
    protected void onStop() {
        super.onStop();
        if (messenger_s!=null) {
            unbindService(conn);
        }
    }
}

5 效果展示

​ 点击【发送】按钮，在服务端可以收到发送的消息，如下：

​ 在客户端收到回复如下：

​ 声明：本文转自【Android】使用Messenger实现进程间通讯